Lead acid storage battery

Abstract

To provide a lead acid storage battery capable of suppressing a leakage of an electrolyte from an external exhaust path to an external part while exhausting a gas generated in a cell chamber from the external exhaust path.SOLUTION: A lead acid storage battery comprises: a battery case; a lid part 12 blocking an opening of the battery case, the lid part having a liquid injection port 12D that is provided in each cell chamber, and has a circular shape when viewed from an upper side; a first thread 12F that is formed on an inner peripheral surface of the liquid injection port; a communication path 20 that is formed above the first thread, and communicating between both of the adjacent liquid injection ports, and a first external exhaust path that is formed above the first thread, and communicates between the liquid injection port provided to a left end part and an external space; and a liquid port valve that blocks the liquid injection port, and includes a second cylinder part, and a second thread formed on the outer peripheral surface of the second cylinder part. The first thread includes a discontinuous section 30 that can be viewed from the upper side, and in the liquid injection port provided to the left end part, at least one part of the discontinuous section 30 is positioned in a region 50 that is located immediately under an opening of the communication path 20 in an inner peripheral surface of the liquid injection port.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The technology disclosed in this specification relates to lead-acid batteries.

Background Art

[0002] Conventionally, in a lead-acid battery having a plurality of cell chambers in which electrodes and an electrolyte are housed, there is known one having an electrolyte tank whose interior is partitioned into a plurality of cell chambers and is open at the top, and a lid portion that closes the opening of the electrolyte tank (see, for example, Patent Document 1).

[0003] Specifically, the lead-acid battery described in Patent Document 1 includes an electrolyte tank and a lid, and a through-hole is formed in the lid. A cylindrical portion continuous with the through-hole is formed in the lid, and the through-hole and the cylindrical portion constitute a liquid injection port. A female screw portion is formed at the base end portion of the inner peripheral surface of the cylindrical portion. After injecting the electrolyte from the liquid injection port into each cell chamber, a liquid port plug is inserted into the liquid injection port, and the male screw portion of the liquid port plug is screwed into the female screw portion of the cylindrical portion, thereby closing each liquid injection port with the liquid port plug.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The above-mentioned Patent Document 1 does not disclose a path for exhausting the gas generated in the cell chamber to the outside.

[0006] This specification discloses a technique for suppressing the leakage of the electrolyte in the cell chamber to the outside from the external exhaust passage while exhausting the gas generated in the cell chamber to the outside through the external exhaust passage.

Means for Solving the Problems

[0007] The lead storage battery disclosed by this specification includes electrodes, an electrolyte, a battery case whose interior is partitioned into a plurality of cell chambers that accommodate the electrodes and the electrolyte and that is open at the top, and a lid that closes the opening of the battery case. The lid is provided for each cell chamber and has a circular liquid injection port when viewed from above, a first thread formed on the inner peripheral surface of the liquid injection port, a communication passage formed above the first thread and communicating the adjacent liquid injection ports with each other, and a first external exhaust passage formed above the first thread and communicating the liquid injection port provided at the first end in the arrangement direction of the cell chambers with the external space. The lead storage battery also includes a liquid port plug that closes the liquid injection port. The liquid port plug has a cylindrical portion that extends vertically inside the liquid injection port, a second thread formed on the outer peripheral surface of the cylindrical portion and screwed with the first thread, and a through hole formed in the outer peripheral wall of the cylindrical portion above the second thread. The first thread has one discontinuous section that is visible from above, and at least a part of the discontinuous section is located in a region on the inner peripheral surface of the liquid injection port provided at the first end and directly below the opening of the communication passage.

Advantages of the Invention

[0008] According to the above configuration, while exhausting the gas generated in the cell chamber to the outside through the external exhaust passage, it is possible to suppress the leakage of the electrolyte in the cell chamber to the outside through the external exhaust passage.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

[0010] [Outline of Embodiment of the Present Disclosure] (1) The lead-acid battery according to the embodiment includes an electrode, an electrolyte, a battery case whose interior is partitioned into a plurality of cell chambers that accommodate the electrode and the electrolyte and that is open upward, and a lid portion that closes the opening of the battery case. The lid portion is provided for each cell chamber and has a circular liquid injection port when viewed from above, a first thread formed on the inner peripheral surface of the liquid injection port, a communication passage formed above the first thread and communicating adjacent liquid injection ports with each other, and a first external exhaust passage formed above the first thread and communicating the liquid injection port provided at the first end in the arrangement direction of the cell chambers with the external space. The lid portion also includes a liquid port plug that closes the liquid injection port, the liquid port plug having a cylindrical portion that extends vertically inside the liquid injection port and a second thread formed on the outer peripheral surface of the cylindrical portion and screwed with the first thread, and a through hole formed in the outer peripheral wall of the cylindrical portion above the second thread. The first thread has one discontinuous section visible from above, and at least a part of the discontinuous section is located in a region directly below the opening of the communication passage on the inner peripheral surface of the liquid injection port provided at the first end.

[0011] The first thread formed on the inner peripheral surface of the liquid injection port may have one discontinuous section visible from above. For example, the first thread may be a single-thread that does not extend around the entire inner peripheral surface of the liquid injection port when viewed from above. This is due to manufacturing reasons such as ease of forming the lid portion and shortening of the time required for forming the lid portion (so-called tact time). In this case, when the direction of proceeding along the first thread from one end to the other end of the first thread when viewed from above is defined as the clockwise direction, the section from the one end to the other end in the counterclockwise direction when viewed from above becomes the discontinuous section visible from above.

[0012] The first thread may be a single-thread or more. Even in the case of a single-thread or more, if there is a notch on the way from one end to the other end of the first thread in the clockwise direction and at least a part of the notched section is visible from above, the range of the notched section that is visible from above becomes the discontinuous section visible from above. If there is a discontinuous section visible from above on the first thread, the electrolyte in the cell chamber may leak upward from the discontinuous section due to vibration or the like, flow into the first external exhaust passage, and leak to the outside.

[0013] According to the lead-acid battery described in (1) above, the liquid injection port provided at the first end in the arrangement direction of the cell chambers (that is, the liquid injection port communicating with the external space through the first external exhaust passage) has at least a part of the discontinuous section located in a region directly below the opening of the communication passage on the inner peripheral surface of the liquid injection port. In other words, when viewed from above, the position of the opening of the communication passage and the position of the discontinuous section overlap in the circumferential direction of the inner peripheral surface of the liquid injection port. By doing so, when the electrolyte leaked from the discontinuous section rises straight up, it becomes easier for the electrolyte that has risen straight up to flow into the communication passage. Therefore, it is possible to suppress the electrolyte from flowing into the first external exhaust passage. Therefore, according to the lead-acid battery described in (1) above, while exhausting the gas generated in the cell chamber to the outside through the first external exhaust passage, it is possible to suppress the electrolyte in the cell chamber from leaking to the outside through the first external exhaust passage.

[0014] (2) The lead-acid battery described in (1) above, wherein the lid portion has a second external exhaust passage that communicates the liquid injection port provided at the second end in the arrangement direction of the cell chambers with the external space, the second external exhaust passage is sealed by a sealing member, and the liquid injection port provided at the second end may have at least a part of the discontinuous section located in a region directly below the opening of the communication passage on the inner peripheral surface of the liquid injection port.

[0015] In a lead storage battery, a liquid injection port provided at a first end in the arrangement direction of cell chambers communicates with an external space through an external exhaust passage, and a liquid injection port provided at a second end also communicates with the external space through another external exhaust passage. Some of them have one of the external exhaust passages sealed by a sealing member. The reason for adopting such a structure is to enable selection of which external exhaust passage to exhaust the gas generated in the cell chamber according to the vehicle or the like on which the lead storage battery is mounted. Here, the external exhaust passage not sealed by the sealing member is referred to as the first external exhaust passage, and the external exhaust passage sealed by the sealing member is referred to as the second external exhaust passage.

[0016] According to the lead storage battery described in (2) above, since at least a part of the discontinuous section is located in a region directly below the opening of the communication passage also at the liquid injection port provided at the second end, even when either of the two external exhaust passages is sealed by the sealing member (in other words, even when either external exhaust passage becomes the first external exhaust passage), leakage of the electrolyte from the first external exhaust passage to the outside can be suppressed.

[0017] (3) In the lead storage battery described in (2) above, when a plurality of the communication passages that are intermittent through the liquid injection port are defined as a batch exhaust passage, each liquid injection port may have at least a part of the discontinuous section located in a region directly below the opening of the communication passage closer to the midpoint in the longitudinal direction of the batch exhaust passage on the inner peripheral surface of the liquid injection port.

[0018] According to the lead storage battery described in (3) above, for liquid injection ports other than those provided at both ends, at least a part of the discontinuous section is located in a region directly below the opening of the communication passage closer to the midpoint in the longitudinal direction of the batch exhaust passage on the inner peripheral surface of the liquid injection port. Therefore, even when either of the two external exhaust passages is sealed by the sealing member (in other words, even when either external exhaust passage becomes the first external exhaust passage), it becomes difficult for the electrolyte to leak to the outside.

[0019] (4) The lead-acid battery according to (1) above, when a plurality of the communication passages and the first external exhaust passage that are intermittent through the liquid injection port are defined as a collective exhaust passage, the liquid injection port other than the liquid injection port provided at the second end in the arrangement direction of the cell chambers is, on the inner peripheral surface of the liquid injection port, at least a part of the discontinuous section is located in a region directly below the opening of the communication passage that is farther from the first external exhaust passage among the communication passages constituting the collective exhaust passage, and the liquid injection port provided at the second end may have the discontinuous section located in a region other than the region directly below the opening of the communication passage on the inner peripheral surface of the liquid injection port.

[0020] According to the lead-acid battery described in (4) above, when the external exhaust passage (i.e., the first external exhaust passage) is provided only on one side, for the liquid injection port other than the liquid injection port provided at the second end, at least a part of the discontinuous section is located in a region directly below the opening of the communication passage that is farther from the first external exhaust passage, making it difficult for the electrolyte leaked from the discontinuous section to leak to the outside. For the liquid injection port provided at the second end, since the discontinuous section is located in a region other than the region directly below the opening of the communication passage, it is difficult for the electrolyte leaked from the discontinuous section to flow into the communication passage. Therefore, for the liquid injection port provided at the second end as well, it is difficult for the electrolyte leaked from the discontinuous section to leak to the outside.

[0021] [Details of Embodiments of the Present Disclosure] Details of the embodiments of the present disclosure will be described below. The present disclosure is not limited to these examples, and is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0022] <Embodiment 1> In the following description, the front-rear direction, left-right direction, and up-down direction are based on the front-rear direction, left-right direction, and up-down direction shown in FIG. 1. In the following description, the reference numerals of the drawings may be omitted for some of the same components.

[0023] (1) Overall Configuration of Lead-Acid Battery Referring to FIG. 1, the lead-acid battery 1 according to Embodiment 1 will be described. The lead-acid battery 1 is mounted on an automobile and supplies power to an engine starting device (starter motor) and auxiliary equipment (such as an electric power steering, an electric brake, a headlight, and an air conditioner). The lead-acid battery 1 is a liquid type and includes a synthetic resin battery case 11 that is open at the top and a synthetic resin lid 12 that closes the opening of the battery case 11.

[0024] As shown in FIG. 2, the battery case 11 is rectangular when viewed from above, and five partition walls 11A are formed at equal intervals in the left-right direction inside. The inside of the battery case 11 is partitioned into six cell chambers 13 by these partition walls 11A. The left-right direction is an example of the arrangement direction of the cell chambers.

[0025] As shown in FIG. 1, the lid 12 has a frame body 12A that extends downward from four sides. A projecting portion 12B that projects upward in a T shape is formed on the lid 12. A positive electrode external terminal 14P is fixed to one of the two corners on the upper surface of the lid 12 where the projecting portion 12B is not formed, and a negative electrode external terminal 14N is fixed to the other corner.

[0026] As shown in FIG. 3, the projecting portion 12B of the lid 12 is formed as a recess that is recessed upward in a T shape when viewed from below. Five partition walls 12C are formed on the back surface of the lid 12 corresponding to the partition walls 11A formed in the battery case 11.

[0027] As shown in FIG. 4, the lower end surface of the partition wall 12C formed on the back surface of the lid 12 is connected to the upper end surface of the partition wall 11A formed in the battery case 11 by heat welding or the like. Thereby, each cell chamber 13 is partitioned. Each cell chamber 13 houses a plate group 15 (an example of an electrode) and an electrolyte 16 made of dilute sulfuric acid. The electrolyte 16 also contains moisture. The plate group 15 is formed by alternately laminating positive electrode plates 15P and negative electrode plates 15N in the horizontal direction with a separator 15C interposed therebetween. Each of the electrode plates 15P and 15N has an active material filled in a grid body.

[0028] As shown in FIG. 5, ears 17 are provided at the upper ends of the respective electrode plates 15P and 15N. As shown in FIG. 4, the ears 17 of the electrode plates 15P and 15N of the same polarity within one cell chamber 13 are connected by a strap 18. The strap 18 is, for example, a plate shape that is long in the left - right direction, and one set of positive - electrode - use and negative - electrode - use straps is provided for each cell chamber 13.

[0029] As shown in FIG. 2, an opening 12K is formed in the partition wall 11A. As shown in FIG. 4, the positive and negative straps 18 of adjacent cell chambers 13 are connected by welding or the like through the opening 12K. Thereby, the electrode - plate groups 15 of each cell chamber 13 are connected in series.

[0030] Referring to FIG. 5, the positive - electrode external terminal 14P and the negative - electrode external terminal 14N will be described. Since the structure of the positive - electrode external terminal 14P and the structure of the negative - electrode external terminal 14N are substantially the same, the positive - electrode external terminal 14P will be described as an example here. The positive - electrode external terminal 14P includes a bushing 14P_1 and a pole 14P_2. The bushing 14P_1 is made of a metal such as a lead alloy and is formed in a cylindrical shape. The upper part of the bushing 14P_1 protrudes upward from the upper surface of the lid portion 12. The pole 14P_2 is made of a metal such as a lead alloy and is formed in a cylindrical shape. The pole 14P_2 is inserted into the inside of the bushing 14P_1 and protrudes downward from the bushing 14P_1. The lower end portion of the pole 14P_2 is connected by welding or the like to the positive - electrode - use strap 18 housed in the left - most cell chamber 13.

[0031] (2) Liquid - injection port As shown in FIG. 1, liquid - injection ports 12D are provided at positions above each cell chamber 13 on the lid portion 12. These liquid - injection ports 12D are arranged in a straight line in the left - right direction. The liquid - injection port 12D is an opening for injecting the electrolytic solution 16 into each cell chamber 13 and is closed by a liquid - port plug 19. The moisture contained in the electrolytic solution 16 evaporates to become water vapor (gas), and may be exhausted to the outside through a batch - exhaust passage 31 (see FIG. 11) described later. When the gas is exhausted and the electrolytic solution 16 decreases, a replenishing liquid is replenished from the liquid - injection port 12D.

[0032] Figure 6 shows cross-sections of the first to third liquid injection ports 12D from the left. In Figure 6, the first liquid injection port 12D from the left is not blocked by the liquid port plug 19. As shown in Figure 6, the liquid injection port 12D has a recessed portion 12D_1 that is recessed in a circular shape, a circular opening 12D_2 formed in the bottom wall of the recessed portion 12D_1, and a first cylindrical portion 12E formed on the lower surface of the lid portion 12. The first cylindrical portion 12E surrounds the opening 12D_2 and extends downward in a cylindrical shape. The inner diameter of the first cylindrical portion 12E is the same as the inner diameter of the opening 12D_2. A first thread 12F that protrudes spirally is formed on the inner peripheral surface of the first cylindrical portion 12E. The first thread 12F is a single-thread screw that does not even go around the inner peripheral surface of the first cylindrical portion 12E once.

[0033] As shown in Figure 3, slits 12G extending upward from the lower end of the first cylindrical portion 12E are formed on the left and right in the first cylindrical portion 12E. The slits 12G are for allowing the gas generated in the cell chamber 13 to flow into the inside of the first cylindrical portion 12E even when the liquid level of the electrolytic solution 16 is above the lower end of the first cylindrical portion 12E.

[0034] (3) Communication passage and exhaust passage As shown in Figure 7, a plurality of communication passage portions 12H, a left exhaust passage portion 12L, and a right exhaust passage portion 12M are integrally formed on the lower surface of the lid portion 12. The plurality of communication passage portions 12H are provided between adjacent first cylindrical portions 12E respectively. A circular cross-section communication passage 20 penetrating in the left-right direction is formed in the communication passage portion 12H. The plurality of communication passages 20 are passages for guiding the gas generated in each cell chamber 13 to the left exhaust passage 23 described later, and are intermittent through the internal space of the first cylindrical portion 12E. Each cell chamber 13 communicates with the communication passage 20 through the internal space of the first cylindrical portion 12E. In the following description, the plurality of communication passages 20 are collectively referred to as a collective exhaust passage 31 (see Figure 11).

[0035] The left exhaust passage portion 12L is provided to the left of the leftmost first cylindrical portion 12E. A left exhaust passage 23 having a circular cross-section penetrating in the left-right direction is formed in the left exhaust passage portion 12L. The left exhaust passage 23 communicates the internal space of the leftmost first cylindrical portion 12E with the accommodation space 12J (the left accommodation space 12J shown in FIG. 7) of an exhaust adapter 21 described later.

[0036] The right exhaust passage portion 12M is provided to the right of the rightmost first cylindrical portion 12E. A right exhaust passage 24 having a circular cross-section penetrating in the left-right direction is formed in the right exhaust passage portion 12M. The right exhaust passage 24 communicates the internal space of the rightmost first cylindrical portion 12E with the accommodation space 12J (the right accommodation space 12J shown in FIG. 7) of the exhaust adapter 21 described later.

[0037] (4) Accommodation Space of Exhaust Adapter As shown in FIG. 6, on the left side surface of the lid portion 12, an accommodation space 12J for accommodating an exhaust adapter 21 (more specifically, the main body portion 21B of the exhaust adapter 21) described later is formed in a recessed shape. The accommodation space 12J is substantially rectangular when viewed from the left. The left exhaust passage 23 opens in the back wall of the accommodation space 12J when viewed from the left. The left exhaust passage 23 and the left accommodation space 12J constitute a first external exhaust passage.

[0038] As shown in FIG. 7, an accommodation space 12J is also formed in a recessed shape on the right side surface of the lid portion 12. The right exhaust passage 24 opens in the back wall of the right accommodation space 12J when viewed from the right. The right exhaust passage 24 and the right accommodation space 12J constitute a second external exhaust passage. However, the exhaust adapter 21 is accommodated only in the left accommodation space 12J, and the right accommodation space 12J is sealed by welding a plate-shaped sealing member 40 made of synthetic resin or the like. The reason for providing the accommodation spaces 12J on the left and right is to enable selection of whether to exhaust gas from the left or right according to the vehicle in which the lead storage battery 1 is mounted. The exhaust adapter 21 may be accommodated in the right accommodation space 12J and the left accommodation space 12J may be sealed. Alternatively, the exhaust adapter 21 may be accommodated in both the left and right accommodation spaces 12J.

[0039] (5) Exhaust adapter Referring to FIG. 8, the exhaust adapter 21 will be described. The exhaust adapter 21 is a component that holds the first filter 21C. As described above, here it is assumed that the exhaust adapter 21 is accommodated in the left accommodation space 12J.

[0040] As shown in FIG. 9, the exhaust adapter 21 has an adapter lid portion 21A that closes the opening of the accommodation space 12J, a main body portion 21B, and a first filter 21C. The adapter lid portion 21A is a plate-shaped member that is slightly larger in size than the accommodation space 12J when viewed from the left, and is fixed to the lid portion 12 by heat welding so as to close the accommodation space 12J. A circular exhaust port 21D is formed in the adapter lid portion 21A.

[0041] The main body portion 21B has a gas inlet 21M that opens upward, an internal passage 21L that guides the gas flowing in from the gas inlet 21M to the exhaust port 21D, a first filter 21C disposed in the internal passage 21L, and a filter support portion 21H that supports the first filter 21C from below inside the internal passage 21L.

[0042] The first filter 21C is mounted for the explosion-proof function of blocking flames from the outside. The first filter 21C also has a role of increasing the exhaust resistance of the gas generated in the cell chamber 13 in cooperation with the second filter 19K disposed in the liquid plug 19 described later. The first filter 21C is formed in a disc shape having a certain thickness. The diameter of the first filter 21C substantially coincides with the inner diameter of the internal passage 21L. The first filter 21C is, for example, a porous body having continuous pores. The porous body is a sintered body of ceramics such as alumina or resin particles such as polypropylene, and the average diameter of the pore diameter is several tens to several hundreds of μm.

[0043] The gas flowing from the left exhaust passage 23 into the accommodation space 12J flows into the internal passage 21L from the gas inlet 21M of the exhaust adapter 21, passes through the first filter 21C, and is exhausted to the outside from the exhaust port 21D.

[0044] (6) Liquid port plug As shown in FIG. 10, the liquid port plug 19 includes a disc-shaped plug member 19A that covers the liquid injection port 12D, a second cylindrical portion 19B (an example of a cylindrical portion) that extends downward in a cylindrical shape from the lower surface of the plug member 19A, and a packing 19C attached to the outer periphery of the upper end portion of the second cylindrical portion 19B.

[0045] As shown in FIG. 1, a groove 19D for screwing the liquid port plug 19 into the inside of the first cylindrical portion 12E with a coin or the like is formed in a cross shape on the upper surface of the liquid port plug 19.

[0046] As shown in FIG. 10, the second cylindrical portion 19B is composed of an upper portion 19E, an intermediate portion 19F, and a lower portion 19G. A second thread 19H is formed on the outer peripheral surface of the intermediate portion 19F. As shown in FIG. 6, the liquid port plug 19 inserted from the liquid injection port 12D is fixed to the lid portion 12 by screwing the second thread 19H into the first thread 12F of the first cylindrical portion 12E.

[0047] The outer diameter of the upper portion 19E of the second cylindrical portion 19B is smaller than the inner diameter of the first cylindrical portion 12E. Therefore, a gap is generated between the inner peripheral surface of the first cylindrical portion 12E and the outer peripheral surface of the upper portion 19E of the second cylindrical portion 19B. The outer diameter of the lower portion 19G of the second cylindrical portion 19B is also smaller than the inner diameter of the first cylindrical portion 12E. Therefore, a gap is also generated between the inner peripheral surface of the first cylindrical portion 12E and the outer peripheral surface of the lower portion 19G.

[0048] As shown in FIG. 10, slits 19J extending upward from the lower end of the second cylindrical portion 19B are formed on the left and right in the lower portion 19G. The slit 19J serves as an entrance for the gas generated in the cell chamber 13 to enter the inside of the second cylindrical portion 19B. The upper end of the slit 19J reaches the lower end portion of the second thread 19H formed in the intermediate portion 19F, and a position where the lower end portion of the second thread 19H overlaps the upper end portion of the slit 19J is cut out.

[0049] As shown in FIG. 6, a disk-shaped second filter 19K having a certain thickness is accommodated inside the upper portion 19E of the second cylindrical portion 19B. The material of the second filter 19K is the same as that of the first filter 21C.

[0050] As shown in FIGS. 6 and 10, circular through-holes 19L are formed on the left and right at positions corresponding to the outer peripheral surface of the second filter 19K in the upper portion 19E of the second cylindrical portion 19B. The through-holes 19L are holes for allowing the gas generated in the cell chamber 13 and passing through the second filter 19K to escape into the communication passage 20.

[0051] Inside the second cylindrical portion 19B and below the second filter 19K, an anti-foaming body 19M is accommodated. The anti-foaming body 19M is for forming a labyrinth-shaped passage inside the second cylindrical portion 19B in order to prevent the mist of the electrolytic solution 16 generated in the cell chamber 13 from reaching the second filter 19K.

[0052] As shown in FIG. 10, a regulating portion 19N for regulating the vertical position of the packing 19C is integrally provided on the outer peripheral surface of the upper portion 19E of the second cylindrical portion 19B. The regulating portion 19N goes around the second cylindrical portion 19B except for the portion where the circular through-hole 19L of the second cylindrical portion 19B is formed. The packing 19C is formed in a ring shape by synthetic rubber or the like. As shown in FIG. 6, when the liquid port plug 19 is inserted into the liquid injection port 12D, the space between the upper surface of the recess 12D_1 of the liquid injection port 12D and the lower surface of the disk-shaped plug member 19A is hermetically sealed by the packing 19C.

[0053] (7) Flow of gas exhaust Referring to FIG. 11, the flow of gas exhaust will be described. For convenience, here, among the six cell chambers 13 shown in FIG. 11, the leftmost cell chamber 13 is referred to as the first cell chamber 13_1, and the second cell chamber 13_2 to the sixth cell chamber 13_6 in order from the left.

[0054] Taking the fourth cell chamber 13_4 as an example, the gas generated in the fourth cell chamber 13_4 flows into the communication passage 20 from the through hole 19L of the liquid port plug 19. The gas flowing into the communication passage 20 flows leftward in the communication passage 20. The gas generated in the cell chambers 13 (the fifth cell chamber 13_5 and the sixth cell chamber 13_6) to the right of the fourth cell chamber 13_4 flows leftward through the space between the first cylindrical portion 12E and the second cylindrical portion 19B of the fourth cell chamber 13_4. The gas flowing leftward flows into the left accommodation space 12J from the left exhaust passage 23.

[0055] (8) Discontinuous section of the first thread Referring to FIG. 12, the discontinuous section 30 of the first thread 12F formed on the inner peripheral surface of the first cylindrical portion 12E will be described. As described above, the first thread 12F has a length that does not reach one full turn around the inner peripheral surface of the first cylindrical portion 12E. Therefore, when viewed from above, both the lower end and the upper end of the first thread 12F are visible. In this case, for example, if the lower end of the first thread 12F is defined as one end and the upper end as the other end, and the direction of proceeding along the first thread 12F from one end to the other end is defined as the clockwise direction, the section from one end to the other end in the counterclockwise direction when viewed from above becomes the visible discontinuous section 30.

[0056] FIG. 13 is a partially enlarged view of the range indicated by the dotted line 61 in FIG. 6. As shown in FIG. 13, in the section of the first thread 12F other than the discontinuous section 30, since it is in close contact with the second thread 19H, in the section other than the discontinuous section 30, it is difficult for the electrolytic solution 16 to leak upward from between the first thread 12F and the second thread 19H. FIG. 14 is a partially enlarged view of the range indicated by the dotted line 62 in FIG. 6. As shown in FIG. 14, in the discontinuous section 30, since the first thread 12F is not in close contact with the second thread 19H, there is a possibility that the electrolytic solution 16 leaks upward from the discontinuous section 30. Therefore, the position of the discontinuous section 30 is set so that even if the electrolytic solution 16 leaks out from the discontinuous section 30, it is difficult to leak to the outside. This will be specifically described below.

[0057] In Fig. 11, the straight line 31 indicated by the dotted line conceptually shows the above-described batch exhaust passage. The point 31P indicates the midpoint in the longitudinal direction of the batch exhaust passage 31. Fig. 15 is a cross-sectional view taken along line B-B shown in Fig. 6. In Fig. 15, since the cross-section is viewed from the left, the opening visible in Fig. 15 is not the opening of the left exhaust passage 23 but the opening of the leftmost communication passage 20. As shown in Fig. 15, the liquid injection port 12D provided at the left end portion (an example of the first end portion) has the entire discontinuous section 30 of the first thread 12F located in the region 50 (the region sandwiched by the two dotted lines 33) directly below the opening of the leftmost communication passage 20 on the inner peripheral surface of the liquid injection port 12D.

[0058] As shown in Fig. 12, the liquid injection port 12D provided at the right end portion (an example of the second end portion) has the entire discontinuous section 30 of the first thread 12F located in the region 50 directly below the opening of the rightmost communication passage 20 on the inner peripheral surface of the liquid injection port 12D. The liquid injection ports 12D other than the liquid injection ports 12D provided at both the left and right end portions have the entire discontinuous section 30 located in the region 50 directly below the opening of the communication passage 20 closer to the midpoint 31P of the batch exhaust passage 31 (see Fig. 11). For example, on the inner peripheral surface of the second liquid injection port 12D from the left, the left communication passage 20 and the right communication passage 20 open with reference to the second liquid injection port 12D. For the second liquid injection port 12D, the right communication passage 20 is the communication passage 20 closer to the midpoint 31P, so the entire discontinuous section 30 is located in the region 50 directly below the opening of the right communication passage 20. The same applies to the third liquid injection port 12D from the left. For the fourth liquid injection port 12D from the left, the left communication passage 20 is the communication passage 20 closer to the midpoint 31P, so the entire discontinuous section 30 is located in the region 50 directly below the opening of the left communication passage 20. The same applies to the fifth liquid injection port 12D from the left.

[0059] (9) Effects of the Embodiment The effects of the lead storage battery 1 according to Embodiment 1 will be described with reference to the comparative example shown in FIG. 17. In the lid portion 312 according to the comparative example, the discontinuous section 30 of the first thread 12F is not located in the region 50 directly below the opening of the communication passage 20. In this case, since the electrolyte 16 leaking from the discontinuous section 30 flows both to the right and to the left, there is a possibility that the electrolyte 16 flowing to the left may leak to the outside.

[0060] On the other hand, as shown in FIG. 12, according to the lead storage battery 1 according to Embodiment 1, the liquid injection port 12D provided at the left end portion (first end portion) (that is, the liquid injection port 12D communicating with the external space through the first external exhaust passage) has the entire discontinuous section 30 located in the region 50 directly below the opening of the leftmost communication passage 20 on the inner peripheral surface of the liquid injection port 12D. In other words, the position of the opening of the communication passage 20 and the position of the discontinuous section 30 overlap in the circumferential direction of the inner peripheral surface of the liquid injection port 12D. By doing so, when the electrolyte 16 leaking from the discontinuous section 30 rises straight up, it becomes easier for the electrolyte 16 that has risen straight up to flow into the communication passage 20. Therefore, it is possible to suppress the electrolyte 16 from flowing into the first external exhaust passage (the left exhaust passage 23 and the left accommodation space 12J). Therefore, according to the lead storage battery 1, while exhausting the gas generated in the cell chamber 13 to the outside through the first external exhaust passage, it is possible to suppress the electrolyte 16 in the cell chamber 13 from leaking to the outside through the first external exhaust passage.

[0061] According to the lead storage battery 1, since the entire discontinuous section 30 is also located in the region 50 directly below the opening of the communication passage 20 in the liquid injection port 12D provided at the right end portion (second end portion), no matter which of the two external exhaust passages is sealed by the sealing member 40 (in other words, no matter which external exhaust passage becomes the first external exhaust passage), it is possible to suppress the electrolyte 16 from leaking to the outside through the first external exhaust passage.

[0062] According to the lead storage battery 1, the liquid injection ports 12D other than the liquid injection ports 12D provided at both ends are located in the region 50 directly below the opening of the communication passage 20 closer to the longitudinal midpoint 31P of the collective exhaust passage 31 on the inner peripheral surface of the liquid injection port 12D, so that the entire discontinuous section 30 is located. Therefore, no matter which of the two external exhaust passages is sealed by the sealing member 40 (in other words, no matter which external exhaust passage becomes the first external exhaust passage), it is difficult for the electrolyte 16 to leak to the outside.

[0063] <Embodiment 2> Referring to FIG. 16, the lid portion 212 according to Embodiment 2 will be described. The lid portion 212 is for exhausting gas only from the right external exhaust passage (right exhaust passage 24 and right accommodation space 12J), and it is not assumed that gas is exhausted from the left external exhaust passage (left exhaust passage 23 and left accommodation space 12J). For this reason, the exhaust adapter 21 is accommodated in the right accommodation space 12J, and the left accommodation space 12J is sealed by the sealing member 40. In Embodiment 2, the right external exhaust passage is an example of the first external exhaust passage, and the left external exhaust passage is an example of the second external exhaust passage. In Embodiment 2, the right end portion is an example of the first end portion, and the left end portion is an example of the second end portion.

[0064] In Embodiment 2, a plurality of communication passages 20 that are intermittent via the liquid injection port 12D and the right external exhaust passage are defined as a collective exhaust path. The liquid injection ports 12D other than the liquid injection port 12D provided at the left end portion are located in the region 50 directly below the opening of the left communication passage 20 (an example of the communication passage farther from the first external exhaust passage among the communication passages constituting the collective exhaust passage) on the inner peripheral surface of the liquid injection port 12D, and the entire discontinuous section 30 is located.

[0065] The liquid injection port 12D provided at the left end portion has only the communication passage 20 on the right. The liquid injection port 12D provided at the left end portion has the discontinuous section 30 located in a region other than the region 50 directly below the opening of the communication passage 20 on the inner peripheral surface of the liquid injection port 12D. That is, for the liquid injection port 12D provided at the left end portion, the discontinuous section 30 is not located in the region 50 directly below the opening of the communication passage 20.

[0066] According to the lead storage battery 1 according to Embodiment 2, when the external exhaust passage (i.e., the first external exhaust passage) is provided only on the right, the injection ports 12D other than the injection port 12D provided at the left end portion are located in the region 50 directly below the opening of the left communication passage 20, and the entire discontinuous section 30 is located in the region 50, so that the electrolyte 16 leaking from the discontinuous section 30 is less likely to leak to the outside. Regarding the injection port 12D provided at the left end portion, since the discontinuous section 30 is located in a region other than the region 50 directly below the opening of the communication passage 20, the electrolyte 16 leaking from the discontinuous section 30 is less likely to flow into the communication passage 20. Therefore, also for the injection port 12D provided at the left end portion, the electrolyte 16 leaking from the discontinuous section 30 is less likely to leak to the outside.

[0067] <Other Embodiments> The technology disclosed by this specification is not limited to the embodiments described by the above description and drawings. For example, the following embodiments are also included in the technical scope disclosed by this specification.

[0068] (1) In the above Embodiment 1, the case where the entire discontinuous section 30 is located in the region 50 directly below the opening of the communication passage 20 is exemplified, but only a part of the discontinuous section 30 may be located in the region 50.

[0069] (2) In the above Embodiment 1, for the injection ports 12D provided at the left end portion (the first end portion) and the right end portion (the second end portion), the entire discontinuous section 30 is located in the region 50 directly below the opening of the communication passage 20, and for the injection ports 12D other than the injection ports 12D at both end portions, the entire discontinuous section 30 is located in the region 50 directly below the opening of the communication passage 20 closer to the intermediate point 31P. In contrast, for the injection ports 12D other than the injection port 12D provided at the left end portion, the discontinuous section 30 may be located at an arbitrary position. The same applies to Embodiment 2. For the injection ports 12D other than the injection port 12D provided at the right end portion (the first end portion), the discontinuous section 30 may be located at an arbitrary position.

[0070] (3) In the above-described Embodiment 1, the case where the entire discontinuous section 30 is located in the region 50 directly below the opening of the right communication passage 20 has been exemplified for the liquid injection port 12D provided at the left end portion (the first end portion). However, the liquid injection port 12D provided at the left end portion does not necessarily have to have the discontinuous section 30 located in the region 50. And, in any one (or a plurality) of the second to fifth liquid injection ports 12D from the left, at least a part of the discontinuous section 30 may be located in the region 50 directly below the opening of the communication passage 20 closer to the intermediate point 31P. The same applies to Embodiment 2. The liquid injection port 12D provided at the right end portion (the first end portion) does not necessarily have to have the discontinuous section 30 located in the region 50 directly below the opening of the communication passage 20. And, in any one (or a plurality) of the second to fifth liquid injection ports 12D from the right, at least a part of the discontinuous section 30 may be located in the region directly below the opening of the communication passage 20 farther from the first external exhaust passage.

[0071] (4) In the above-described embodiment, the case where the first thread 12F is a single-threaded screw having a length less than one turn around the inner peripheral surface of the liquid injection port 12D has been exemplified. However, the first thread 12F may be single-threaded or multi-threaded. Even in the case of single-threaded or multi-threaded, if there is a notch on the way from one end of the first thread 12F in the clockwise direction (the direction of advancing along the first thread 12F from one end of the first thread 12F to the other end) to the other end, and at least a part of the notched section is visible from above, the visible range of the notched section from above becomes a discontinuous section visible from above.

[0072] (5) In the above-described embodiment, the case where the plurality of liquid injection ports 12D are arranged in a straight line has been exemplified. However, the liquid injection ports 12D do not necessarily have to be arranged in a straight line. For example, the liquid injection ports 12D may be arranged in a zigzag shape.

[0073] (6) In the above-described embodiment, the case where the lid portion 12 has a single-layer structure has been exemplified. However, the lid portion 12 may have a double-layer structure composed of an upper lid and a lower lid. And, a communication passage 20, a first external exhaust passage, etc. may be formed between the upper lid and the lower lid.

[0074] (7) The liquid port plug 19 illustrated in the above embodiment is an example, and an appropriate structure can be adopted.

[0075] (8) The exhaust adapter 21 illustrated in the above Embodiment 1 is an example, and an appropriate structure can be adopted. For example, the gas inlet of the exhaust adapter 21 may open downward or may open in the horizontal direction.

[0076] (9) In the above embodiment, the case where the number of the liquid injection ports 12D is even is illustrated, but it may be odd. In that case, the discontinuous section 30 of the first thread 12F of the central liquid injection port 12D may be located at an arbitrary position in the circumferential direction of the inner peripheral surface of the liquid injection port 12D. The central liquid injection port 12D refers to, for example, the fourth liquid injection port 12D from the left (or right) when the number of the liquid injection ports 12 is 7.

Explanation of Reference Numerals

[0077] 1: Lead-acid battery 11: Battery case 12: Cover part 12D: Liquid injection port 12F: First thread 12J: Accommodation space (the left accommodation space is an example of the first external exhaust passage, and the right accommodation space is an example of the second external exhaust passage) 13: Cell compartment 15: Electrode plate group (an example of an electrode) 16: Electrolyte 19B: Second cylindrical part (an example of a cylindrical part) 19H: Second thread 19L: Through hole 20: Communication passage 23: Left exhaust passage (an example of the first external exhaust passage) 24: Right exhaust passage (an example of the second external exhaust passage) 30: Discontinuous section 31: Bulk exhaust passage 31P: Intermediate point 40: Sealing member 50: Region directly below the opening of the communication passage

Claims

1. An electrode, an electrolytic solution, a battery case whose interior is partitioned into a plurality of cell chambers that accommodate the electrode and the electrolytic solution and that is open at the top, a lid portion that closes the opening of the battery case, a circular liquid injection port provided for each of the cell chambers and circular when viewed from above, a first thread formed on the inner peripheral surface of the liquid injection port, a communication passage formed above the first thread and communicating the adjacent liquid injection ports with each other, a first external exhaust passage formed above the first thread and communicating the liquid injection port provided at the first end in the arrangement direction of the cell chambers with the external space, a lid portion having the above, a liquid injection port plug that closes the liquid injection port, a cylindrical portion extending in the vertical direction inside the liquid injection port, a second thread formed on the outer peripheral surface of the cylindrical portion and screwed with the first thread, a through hole formed in the outer peripheral wall of the cylindrical portion above the second thread, a liquid injection port plug having the above, comprising, the first thread has one discontinuous section that is visible from above, the liquid injection port provided at the first end is a lead storage battery in which at least a part of the discontinuous section is located in a region directly below the opening of the communication passage on the inner peripheral surface of the liquid injection port.

2. The lid portion has a second external exhaust passage that communicates the liquid injection port provided at the second end in the arrangement direction of the cell chambers with the external space, the second external exhaust passage is sealed by a sealing member, the liquid injection port provided at the second end is a lead storage battery according to claim 1, in which at least a part of the discontinuous section is located in a region directly below the opening of the communication passage on the inner peripheral surface of the liquid injection port.

3. When a plurality of the communication passages that are intermittent through the liquid injection port are defined as a batch exhaust passage, each of the liquid injection ports is such that at least a part of the discontinuous section is located in a region directly below the opening of the communication passage closer to the midpoint in the longitudinal direction of the batch exhaust passage on the inner peripheral surface of the liquid injection port. The lead storage battery according to claim 2.

4. When a plurality of the communication passages that are intermittent through the liquid injection port and the first external exhaust passage are defined as a batch exhaust passage, liquid injection ports other than the liquid injection port provided at the second end in the arrangement direction of the cell chambers are such that at least a part of the discontinuous section is located in a region directly below the opening of the communication passage that is farther from the first external exhaust passage among the communication passages constituting the batch exhaust passage on the inner peripheral surface of the liquid injection port. The lead storage battery according to claim 1, wherein the liquid injection port provided at the second end portion has the discontinuous section located in a region other than a region directly below the opening of the communication passage on the inner peripheral surface of the liquid injection port.

Images